1. Field of the Invention
The present invention relates to an ETC (electronic toll collection system) car-mounted equipment having a mirror unit. More particularly, the invention relates to an ETC car-mounted equipment which can be attached to an existing room mirror in a vehicle and enhances operability impairing neither the communication function nor the visual range for operation.
2. Prior Art
An electronic toll collection system called ETC has heretofore been known, and an ETC car-mounted equipment has been known too, the ETC equipment being mounted on a vehicle to exchange the data related to the balance and toll (hereinafter referred to as "ETC data") relative to an ETC road equipment.
The ETC car-mounted equipment has an antenna unit which includes an antenna element and an RF substrate, and must be installed at such a position in a vehicle where the communication function can be maintained between the antenna unit and the ETC road equipment without impairing the visual range for operation.
Japanese Unexamined Patent Publication (Kokai) No. 297758/1996 discloses an ETC car-mounted equipment having a mirror unit, which is incorporated in a room mirror in the vehicle as a unitary structure.
FIG. 10 is a perspective view schematically illustrating the constitution of a conventional ETC car-mounted equipment having a mirror unit.
In FIG. 10, a main body 3 of the ETC car-mounted equipment is attached, via a stay (not shown), to a roof 2 in the room of a vehicle so as to be located at an upper part of a windshield 1 of the vehicle.
The main body 3 of the car-mounted equipment includes a mirror unit 4 provided on the upper surface of a front closure that can be opened and closed, an antenna unit 5 provided on the back surface side, an IC card insertion port 6 in which will be inserted an IC card 10 for storing ETC data, a display unit 7 for displaying ETC data, a key switch 8 including ten keys for inputting data, and a buzzer 9 for alarming abnormal condition.
In the constitution of FIG. 10, the IC card 10 is inserted in the IC card insertion port 6 of the main body 3 of the car-mounted equipment, whereby the specific ETC data are read out to specify a person who uses the vehicle and the ETC car-mounted equipment.
Therefore, the ETC car-mounted equipment functions preventing the chances of being used without authorization, and the antenna unit 5 executes communication with the ETC road equipment (not shown) installed at a toll gate of a toll road. Accordingly, a toll for using the road is automatically collected and settled based upon a wireless communication.
Here, the main body 3 of the car-mounted equipment in which the IC card 10 will be inserted, is incorporated in the existing room mirror as a unitary structure. When the front closure is closed, the mirror unit 4 serves as a room mirror without interrupting the visual range for operation.
To input the data or command, the driver opens the front closure having the mirror unit 4 and manipulates the key switch 8 to input any data or command.
As described above, the conventional ETC car-mounted equipment has been constituted together with the room mirror as a unitary structure. Therefore, the ETC car-mounted equipment must be incorporated at the time when the vehicle is being assembled in a plant. In other words, it is difficult to attach the ETC car-mounted equipment after the vehicle has been assembled. Depending upon the models of vehicles, furthermore, the directivity of the antenna unit 5 is not often set in an optimum manner.
To input the data, furthermore, the front closure fabricated together with the mirror unit 4 must be opened; i.e., the data are not easily input and, besides, the mirror unit 4 does not function while it is being opened.